Lens grinding and polishing machine.



E. STEAD.

LENS GRINDING AND POLISHING MACHINE.

APPLICATION FILED JUNE II I9I5.

1,230,530. Patented June 19, 1917.

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APPLICATJQN FILED JUNE 1; I915- Patented June 19, 1917.

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UNITED STATES PATENT OFFICE.

ERNEST STEAD, OF BINGHAETON, YORK.

, LENS GRINDING AND POLISHIN G MACHINE.

Specification of Letters Patent. Patented June 19, 1917.

Application filed June 1, 1915. Serial No. 31,538.

To all whom it may concern:

Be it known that I, ERNEST STEAD, a citi zen of the United States ofAmerica, and resident of Bin hamton, in the county of Broome, in thetate of New York, have vented new and useful Improvements in LensGrindin and Polishing Machines, of

ished under a combined rotary and planetary action of the ments.

Another object is to enable the machine to be easily and quicklyadjusted for grinding grinding or polishing elethe surfaces of differentforms of lenses without affecting the speed ratios or direction ofmovement of the rotary or planetary motions.

A further object is to provide simple means for slightly shifting one ofthe grinding or polishing elements relatively to the other to preventthe recurrence of contact at any one point between the work and tool inorder to reduce to a minimum the liability of producing channels or linemarks in the lens.-

Other objects and uses relating to specific parts of the machine will bebrought out in the following description.

In the drawings Figure 1 is a front elevation of a lensgrinding andpolishing machine embodying the various features of my invention.

Fig. 2 is an enlarged vertical sectional piew of the same machine takenon line 2-2,

Fig. 3 is an enlarged horizontal sectional view taken on line 3'-3, Fig.1.

Fig. 4 is a vertical sectional view taken in the plane of line H, Fig.3.

Fig. 5 is a vertical sectional view through the gear case under thetable, taken in the plane of line 55, Fig. 2, and showing a portion ofthe motor shaft and its clutch connection with the gear shaft.

Fig. 6 is a top plan of the electric switch 'for controlling theoperation of the motor and adjacent portion of its operating mechanism.

Fi 7 is a vertical sectional View taken on line 5-7, Fig. 6. Fig. 8 is adiagrammatic plan of the rotary grinding or polishing tool and rotarylens holder showing their relative directions of movement.

As illustrated, the machine comprises a main frame -l adapted to restupon the floor and having a substantially horizontal bed or table 2 forsupportin the various mechanism at the desired heig t for convenience ofoperation and inspection of the various mechanisms and work, the tableor bed 2 being provided with a circular vertical opening 3 therethroughfor receiving certain portions of the driving mechanisms for the tooland work and also provided with a raised annular flange 4 surroundingthe opening and concentric therewith, but some distance therefrom forretaining any loose tools or Work which may be temporarily supportedupon the bed against accidental displacement.

Secured to the lower and upper faces of the bed or table '2, co-axialwith the opening 3, are gear case sections -5- and 6 having suitablebearings 7 and 8 centrally in their adjacent ends for receiving andsupporting the adjacent portion of a vertical shaft 9, the lower end ofthe case section 5 and the upper end of the case section 6 being closedby caps 10- and ,11, respectively, for excluding dust and other foreignmatter from the working parts Within the case.

The lower end of the shaft 9- is journaled in a bearing 12 in the bottom.of the cap 10 and is provided with an anti-friction end thrust bearing13-, shown more clearly in Figs. 2 and 5, the intermediate portion ofsaid shaft being connected by beveled gears --14 to B. horizontal shaftsection l5 which in turn is connected by a clutch or coupling 16 to aco-axial armature shaft -17 of an electric motor 18, the latter beingsecured in a horizontal. position to the under side of trio switch -l9-of any suitable construction capable of controlling the operation of themotor, and preferably of a snap-switch type having an operating memberor handle by which the rotary part thereof may be operated. I

It is preferable, however, to provide means whereby it may be operatedby the foot, and for this purpose the rotary shaft to which the handleis attached is provided with a ratchet wheel -21 adapted to be engagedby a pawl 22 on a co-axial rock arm -23- which is loose on the switchshaftand is connected by a link -2 l to one arm of a bell crank lever 25on the under side of the bed or table -2-, as shown more clearly inFigs. 1, 6 and 7, the other arm being attached to a vertical operatingrod 26- extending to a point near the floor line and provided with apedal ;-27, whereby the rod may be depressed by the foot of theoperator.

The rod -26 is guided in bearings 28- on one of the supporting legs ofthe table 2 and is retracted by a coil spring 29 surrounding the upperend of the rod between the uppermost bearing 28- and a shoulder 30 onthe rod, as shown in Fig.1, the spring serving not only to 301 retractthe rod 26, but also to return the rock arm 23- and pawl 22- to theirstarting positions to engage the next adjacent tooth of the ratchetwheel --21.

The binding post as -31 of the switch may be connected by wires -32 toany available source of current supply capable of operating the motor.

In order that the tool holder as 33 carrying the grinding tool or lap asa eegmay be driven at the desired speed, it is secured by a set screw34- to the upper end of a shaft extension 5 co-axial with but separatefrom the shaft 5 and connected to said shaft by suitable gearingpresently described.

The upper end of the shaft 5 is tapered and tightly fitted in acorresponding socket of a sleeve 35, telescoping within another sleeve-36 on the lower end of the shaft section 5 so that the two shafts maybe rotated relatively to each other at the same or different speeds, thesleeves and shaft sections 5 and 5 being held exactly co-axial andagainst relative endwise movement by anti-friction end thrust bearings'37-.

The lower end of the sleeve 5 is provided with a pinion 38 meshing witha relatively larger gear 39 on an upright countershaft l0 which isjournaled in suitable bearings in the bottom and top of the case 6- andis provided with a pinion 41- meshing with a relatively larger gear 42-on the lower end of the sleeve -36 thus completing the gear train fornaaonao transmitting rotary motion from the shaft -5-- to the co-axialshaft section -5' carrying the tool holder 33 andcausing the tool holderto be rotated at a lower rate of speed than that of the motor, the gear-14 on the shaft 5- being also relatively larger than that on the motorshaft extension -15.

The shaft 5'- is not only journaled at its lower end upon the sleeve-35-, but is also journaled intermediate its ends in a bearing -43 onthe cap 11 close to the tool holder 33 which serves to maintain an exactco-axial relation between the tool holder and its driving shaft 5-, andalso reduces to a minimum the liability of vibration of the tool holderwhich might affect the accuracy of the grinding of the surface of thelens.

The lens as b is secured in the usual manner by paste or other adhesiveto one of two relatively movable lens-holding sections -44 of anywell-known construction, the other section being rigidly secured to acentering pin or spindle l5 on one of the sections as 46- of a flexibleshaft r-l7 to move endwise therein, and together with the lens holder Mis spring pressed toward the tool -w by a coil spring 48 acting upon theinner end of the centering pin or spindle which is keyed to the shaftsection -et6 by a screw 49 to rotate therewith, the screw -49 beingpassed through a slot -50 in the adjacent side of the shaft section 46to allow relative endwise movement of the parts 45 and 46, thuspermitting the lens holder to be lifted from the grinding or polishingtool wagainst the action of the spring 48 to remove the section to whichthe lens is secured when desired for inspection or other purposes.

The upper end of the shaft section 46 is connected by a universal joint-51 to an upwardly extending shaft section --52 which is feathered orsplined to an adjacent shaft section .53 to rotate therewith and allowthe sections to be adjusted lengthwise of each other, the section 53being connected by a universal joint 5% to a vertical shaft section 55.

This section 55- is journaled in the front end of a horizontal bracket-56 coaxial with the axis of movement of the tool holder 33- and isconnected by gears 57-to a horizontal shaft -58 also journaled inhearings in the bracket 5( which is secured to an upright standard -59rising from the rear side of the bed or table 2-.

The rear end of the upper horizontal shaft 58 is connected by beveledgears -60 to an upright shaft 61 which is journaled at its lower andupper ends in bearings 62- on the standard -59- and is connected at itslower end by beveled gears 63 to a forwardly extending horizontal shaft64-.

This shaft -64' is journaled in suitable bearings 65- on a rearwardextension 66 of the case 6 and is connected by beveled gears 67 to thesleeve 36 on the lower end of the shaft section 5 so that the toolholder and work holder are driven from the same source of power and,therefore, in synchronism, the gear connections between the shaft -5 andflexible shaft '47 being so arranged and proportioned as to drive thework holder in the same direction and at the same rate of speed as thetool holder.

Planetary motion.

In grinding or polishing cylindrical, spherical or toric surfaces ofdifferent degrees of curvature by means of a rotary tool, it isdesirable to progressively shift the position of the lens relatively tothe tool so as to avoid cutting circular lines or channels in the lensby regular recurrent rubbing contact between the same points of the lensand tool, and for this purpose, I have provided means for impartin ,aplanetary motion to the lens holder relatively to the tool, but in anopposite direction, and at a different rate of speed, in this instance,one-fourth the speed of movement of 'the tool and lens holder abouttheir respective axes so that when these parts are properly set at thebeginning of the operation for grinding a torio lens, the correspondingaxes of the diiferent curves of the tool and lens are always registeredwith each other on each quarter turn of the tool or lens holder.

These results are accomplished by deflecting and holding a portion ofthe flexible shaft -47 to one side of the axis of the tool holder andthen rotating the deflected portion about said axis, the degree ofdeflection depending upon the degree of curvature of the grinding orpolishing surface to bring the axis of the lens-supporting spindle 45approximately radial to such surface, and for this purpose, the shaftsec: tion 46 carrying the lens supporting spindle 45 is journaled in asleeve -68 passing through a slotted plate -69 and held against rotationby radial pivotal pins -70 in opposite sides of the plate and enteringholes in opposite sides of the sleeve to allow the latter to adjustitself to different angles as the plate is adjusted in setting theflexible shaft section 46- at the desired angle, after which the sleeveis held in its adjusted position by a set screw -7l, Figs. 3 and 4.

The late 69 and portion of the flexible shaft passing therethrough arearranged within a relatively large horizontal gear -72 which isjournaled in a suitable The rear end of the horizontal shaft 78 isconnected to the upright shaft 61 by beveled gears '81-, thussynchronizing the rotation of the gear 72 and planetary movement of thelens holder with the rotary movement of the tool holder, the ratio ofthe gears 72- and 8l being four to one so that the lens holder willtravel one-fourth of its 0 ole during each revolution of the tool holer, thereby causing like' axes of the tool holder and lens to registereach quarter revolution of those parts about their respective axes whichis important, particularly in grinding toric' lenses.

In order to further reduce the liability of cutting objectionablegrooves or channels in the lenses during the grinding or polishingoperation, I have provided simple means for shifting the lens holderback and forth relatively to its orbit consisting, in this instance, ofa pair of eccentrics 82 mounted upon a horizontal shaft 83 which isjournaled in suitable bearings on the upright standard -59 and is drivenfrom the upright shaft 6l by angle gears 8 1, said eccentricsbeingconnected by pitmen 85- to opposite sides of the frame 74., as shownmore clearly in Fig. 3, said frame being movable along and upon ways -86on the front end of the bracket 7 When the slide 69 is adjusted to thedesired position, it is held in such position by means .of a set screw 71, thereby causing the lens to travel in a circular orbit around andupon the face of the tool --a', it being understood that the gear 72 isco-axial with the axis ofthe tool holder 33 and mandrel 55 and that thedegree ofadjustment of the slide 69 depends upon the curvature of thesurface of the tool.

It is also evident that in grinding convex surfaces, the slide and lensholder will be at the same side of the axis of the tool holder, while ingrinding concave lenses, the slide and lens holder will be at oppositesides of said axis without changing the speed or direction of planetarymotion of the lens.

What I claim is:

1. In a lens grinding and polishing machine, a rotary work holderadjustable to different angles relatively-to the axis of the toolholder, means for locking the work holder in its adjusted position, a,rotary tool holder, and mechanism for rotating the work holder and toolholder in the same direction and at the same rate of speed.

2. In a lens grinding and polishing ma chine, a rotary tool holder and arotary lens holder cooperating therewith, means for driving the toolholder and lens holder in the same direction and at the same rate ofspeed, additional means for moving the lens holder in an orbit about theaxis of, but in an opposite direction to and at a different rate ofspeed than the tool holder, and cooperative means for reciprocating thelens holder relatively to its orbit and during its planetary motion.

3. In a machine for grinding and polishing lenses, co-axial rotary shaftsections, driving means for one of said sections, a tool holder carriedby one of the sections to rotate therewith, 'means for driving the othersection, means driven by the lastnamed section for driving thetool-carrying section at a different rate of speed, a lensholdingsection cooperating with the tool holder, means for moving the lensholder in an orbit about the axis of the tool holder, but in an oppositedirection and at a different rate of speed, and additional means forrotating the lens holder in the same direction and at the same rate ofspeed as the tool holder.

4. In a lens grindingand polishing machine, a rotary tool holder andactuating means therefor, in combination with a mandrel co-axial withthe tool holder, a flexible shaft connected to the mandrel, a lensholder on the flexible shaft, means for rotating the mandrel in the samedirection and at the same rate of speed as the tool holder, andadditional means for deflecting a portion of the flexible shaft to oneside of said axis and rotating it in an orbit about the same, but at aless speed than that of the mandrel and tool holder.

5. In a lens grinding and polishing machine, in combination with arotary tool holder and actuating means therefor, a revoluble memberco-axial with the tool holder,

naeonac driving means for said member, a rotary shaft passing throughsaid member and adjustable toward and from its axis, means for holdingthe portion of the shaft paming through the member in its adjustedposition, a lens holder carried by the shaft to 00- operate with thetool holder, means for rotating the shaft, and additional means forivleiziprocating said revoluble member radia y.

6. In a machine for grinding and polishing lenses, the combination ofthe grinding element, a rotary shaft carrying a work holder, means foradjusting, the work holder shaft to different angles relatively to thegrinding element, and means for carrying said shaft at the adjustedangle in a planetary motion about the produced axis of the grindingelement.

7. In a machine of the character described, the combination of a rotarytool holder and actuating means therefor, a flexible shaft having a workholder thereon, and means for deflecting a ortion of said shaft to oneside of a direct ine between its ends and for rotating such deflectedportion in an orbit about the produced axis of the tool holder.

8. In a machine of the character described, the combination of a toolholder and a cooperative work holder, shaft sections connected by auniversal joint, the work holder being secured to one of said shaftsections, means for deflecting the shaft sections at the joint and forholding them at an angle to each other, and means for moving the jointin an orbit about the produced axis of the tool holder.

9. In a machine of the character described, the combination of a rotarytool holder and actuating means therefor, a work holder and a rotarydriving element therefor adjustable to different angles relatively tothe axis of the tool holder, and means for holding said element in itsadjusted position and for moving it in an orbit about said axis.

In witness whereof I have hereunto set my hand this 24th day of May,1915.

ERNEST STEAD, Witnesses:

THOMAS E. DILLON, CARL F. JoENsoN.

